Thanks for all the suggestions, good and not so good, but her mum is out all day so I'll be looking after her on my own. She's not big enough for the child seat yet so that option is out.
Get the tube and come and spectate. There is a kids play area in Waterlow park (next to Swains Lane) for when she gets board.
Get the tube and come and spectate. There is a kids play area in Waterlow park (next to Swains Lane) for when she gets board.